A known system for performing in-flight refueling operations, illustrated in FIGS. 1 to 3, is based on a refueling device 15 allowing fuel to pass from a tanker aircraft 13 to a receiver aircraft 11.
The refueling device 15 comprises a hose and drogue device 17 in the tanker aircraft 13 and a probe 25 in the receiver aircraft 11.
The hose and drogue device 17 comprises a flexible hose 19 that trails from a refueling unit (pod or FRU) located in the tanker aircraft 13, a reception coupling unit 23 at the end of the hose 19 which has a passage for receiving the nozzle of the probe 25, and a drogue 21 which is a fitting resembling a windsock or shuttlecock that is used to stabilise the hose 19 trailing from the tanker aircraft 13 and to provide the drag to maintain the hose catenary and the mating force with the probe 25.
The hose and drogue device 17 is extended and retracted from and to a drum device 35 that includes a winding drum for extending and retracting the hose 19 and a motor to actuate the winding drum. When not in use the hose 19 is reeled completely into the winding drum.
The probe 25 is a rigid arm placed on the receiver aircraft's nose or fuselage with a valve that is closed until it mates with the reception coupling unit 23 and is opened to allow fuel to pass from the tanker aircraft 13 to the receiver aircraft 11.
The fuel is pumped out from a fuel tank 31 to the hose 19 by means of a fuel pump 33.
A control unit 41 operatively connected with the fuel pump 33 and the drum device 35 manages the extension and retraction of the hose and drogue device 17 and the supply of fuel to the hose 19.
The motion of the hose and drogue device 17 during an in-flight refueling operation is subject to many forces that can vary throughout the in-flight refueling process. An improper control of the hose and drogue device in response to such forces can create significant risks for the receiver aircraft 11 and may cause missed contacts between the drogue and receiver aircraft. For example, the hose and drogue device 17 may break due to improper control and the forces applied to the device.
While the prior art has proposed solutions to particular problems such as US 2006/0060709 for the whipping of the hose and drogue device during the contact phase, a comprehensive control of the motion of the hose and drogue device 17 during all the in-flight refueling phases has not yet been achieved.